Beware of the whooping cough this winter

Thousands of Kiwi adults living with common respiratory diseases such as asthma risk potentially life-threatening complications from whooping cough this winter.

The warning comes with the country experiencing a nationwide outbreak of whooping cough with over 4,690 New Zealanders contracting the disease since it began in 2017.

Whooping cough is a common and potentially deadly illness caused by the bacterium Bordetella pertussis, rivalling measles as one of the most contagious diseases affecting the human population.

Rates of whooping cough are higher in Maori and Pasifika people aged 15+, with rates of respiratory diseases such as asthma and chronic obstructive pulmonary disease or COPD also a significant health issue in these populations.

Internationally, New Zealand has a high prevalence of asthma with one in eight adults reporting taking current asthma medication. New Zealand also has one of the highest hospital admission rates for asthma of OECD countries and pre-existing asthma can increase the rate of hospitalisation from pertussis.

Similarly, COPD, which is a term covering emphysema, chronic bronchitis and chronic asthma, is the fourth leading cause of death nationwide. One in seven adults over 45 have COPD with hospitalisation rates highest for Maori.

The rate of hospitalisation as a result of this respiratory disease are also five times higher in the most deprived areas than in the least deprived.

Dr Helen Petousis-Harris, Vaccinologist and Senior Lecturer, Dept General Practice and Primary Health Care of the University of Auckland says although generally not severe in otherwise healthy adults, pertussis can be associated with serious complications in patients with existing chronic conditions such as obesity, asthma or COPD, and can be readily transmitted to other vulnerable populations, including infants before they complete their first vaccination.

She says while awareness is growing for the need to get vaccinated for influenza at this time of year, the burden of whooping cough among the adult population is widely underestimated and there is a clear rationale for extending vaccination throughout life to prevent disease in this group.

“While the focus is often on ensuring the protection of infants, there are other susceptible members of the community that risk serious health complications from whooping cough.

“For someone who lives with asthma or COPD, contracting pertussis could be life-threatening as these pre-existing respiratory diseases leave them more vulnerable.

“In the same way we advise protecting infants from exposure to whooping cough, it is important for adults living with asthma or COPD, as well as their whanau to look at immunising themselves against this highly contagious disease,” she says.

Helen says whooping cough immunity from childhood vaccinations will wane over time and will need booster shots to help prevent disease later in life.

Dr Helen Petousis-Harris, Vaccinologist and Senior Lecturer, Dept General Practice and Primary Health Care of the University of Auckland.

She says exposure to colds and influenza during winter may further impact on the body’s ability to protect itself.

According to latest figures from the Institute of Environmental Science and Research, more than half of the 2,110 whooping cough cases notified over the past twelve months were adults aged 20+, with this age group representing 45% of hospitalisations. Maori and Pasifika make up the bulk of adults who contract the disease.

Helen says local research into Kiwis’ awareness of pertussis suggest they fail to understand how readily the disease can be transmitted.

The research found that almost all of respondents had heard of whooping cough, however only a quarter of respondents say they were vaccinated for whooping cough and had received a booster shot.

A further 29 per cent say they had been vaccinated but had not had a booster and almost half of NZ adults were unaware whether they were vaccinated or had received a booster against whooping cough.

Guidelines recommend whooping cough booster vaccinations for adults who are at risk of severe illness or complications from the disease, such as those with chronic respiratory conditions, every ten years.

Under a new proposal, Pharmac are set to widen access to the whooping cough vaccination for adults aged 45 and 65, pregnant women in their second and third trimesters, as well as for parents and primary caregivers of infants admitted to a Neonatal Intensive Care Unit or Specialist Care Baby Unit for more than three days.

Helen says adults are also at risk of other complications including rib fractures, weight loss, and urinary incontinence syncope from severe coughing.

“It is possible to reduce the risk of catching and spreading this disease - if you’re pregnant, in close contact with an infant or have asthma/COPD you need to talk to your health care professional about getting a booster shot,” she says.